Fuel burner



Nov. 4, 1952 s. F. OLSEN FUEL BURNER Filed May 5, 1951 IN V EN TOR.

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Patented Nov. 4, 1952 FUEL BURNER George F. Olsen, Colton, Calif., assignorito California Portland Cement Company, Los Angeles, Calif., a corporation of California Application May 5,1951, SerialNmZZQlSB;

.1. Claim. 1

This invention relates to improved furnace burners having certain broad features of novelty as applied to the burning of natural gas and similar fuels, but more particularly characterized in other respects by a unique capacity for selectively burning either of two different fluid fuels, as for instance fuel oil and natural gas.

Many operators of normally oil burning industrial furnaces are located in areas where a cheaper fuel, such as natural gas, is available on an interruptible or non-continuous basis. In order to take advantage of such cheaper fuels, various burner arrangements have been devised for permitting a furnace to be flred selectively by either gas or oil, as desired. However, all of these double fuel arrangements with which I am acquainted have proven either inefiicient in operation or relatively difficult to convert between fuels.

As an example, one double fuel expedient heretofore suggested has employed two separate burner assemblies for burning the two fuels respectively, the two assemblies being permanently mounted at different locations in the furnace. This system, however, has the disadvantage that only one of the burners can be positioned at the most desirable firing location in the furnace, with a resulting loss of efficiency when the other burner is in operation. A second arrangement has employed two burner assemblies mountable selectively at the same location in the furnace, one burner being entirely removed and the other mounted in its place when a change in fuel is desired. As will be readily appreciated, such removal and replacement of burners must necessarily be rather inconvenient and result in the frequent needless expenditure of both time and effort;

A major object of the present invention is to provide a single burner assembly adapted to selectively burn either of two fluid fuels, such as oil and gas. and capable of converting between these two fuels virtually instantaneously. Particularly contemplated is a burner adapted for such fuel interchange, and in addition so designed that both fuels are burned with maxi mum efficiency and at exactly the same point in the furnace, to under all conditions maintain optimum firing characteristics.

To maximize the efficiency of the burner itself, I provide within the burner a unique baffle arrangement adapted to produce a special flame pattern at all times. More specifically, the flame, instead of flaring or spreading in the usual, manner, forms. an. elongated shaft-like pattern projecting straightoutwardly from the burner. Preferably, the fuel and air are so confined and directed in the burner as to shape this elongated shaft of flame into a highly efficient cylindrical configuration. The burner may be so constructed as to permit the adjustment of the flame from such an elongated shaft to a short flaring flame when desired. Further ad justments may be provided for varying the. relative rates of oil, gas and air flow.

As is well known, the burning of natural gas produces a somewhat less intense flame than fuel oil. With this in mind, a further object of the invention isto provide a convertible burner of the above type so designed that when gas is being burned, a small andcontrol-lable amount of oil may be mixed and burned with the gas, to add to the intensity-of the flame.

Structurally, a burner embodying the present invention may include a. tubular body through which a stream of. air flows for delivery from an open discharge end, means within the body for selectively or together introducing streams of oilfand gas into the air. stream, and a spreader bailie positioned in. both the oil and gas streams and deflecting. both fuels into intimate mixture with the air. By. virtue of. the use of such a common. spreader bafile for. both the oil and. gas, both fuels a'red'eflected into. the air stream in precisely the same. manner, and the discharged flame is in each case the same.

Certain highly important'features of the invention involve the unique. preferred construction of the fuel directing/spreader baffle in a manner to produce the above discussed elongated shaft-like flame pattern. Specifically, this baffle may be so constructed as topres'ent to the fuel first a flaring. outer surface deflecting the fuel into intimate mixture with the air, and then an outer surface of uniform. transverse. section which acts to directthe fuel-air mixture directly outwardly from the burner and thus" produce an elongated shaft'of flame. Preferably, the inner surface of the. burner. body is ofv uniform transverse section opposite the uniform surface of the bafiie, to coact with it in producing. the desired flame pattern. Bothof' thee uniform cross sec endmay carry the spreader ba'ffie, and-desirably contains a valve by which the flow of fuel oil through the inner tube is controlled. This valve may take the form of a needle valve having a ta pered seating portion at the discharge end of the inner tube, and having an actuating stem extending axially through the tube to an outer end accessible to an operator.

The above and other features and objects of the present invention will be better understood from the following detailed description of the typical embodiment illustrated in the accompanying drawing, in which:

Fig. l is a side view of a combination oil and gas burner, showing diagrammatically the connection of the burner to an oil supply pump and gas compressor;

Fig. 2 is an enlarged vertical sectional view 2 taken longitudinally through the burner of Fig. 1; Figs. 3 and 4 are transverse sections through the burner, taken on lines 3-3 and 4-4 respectively of Fig. 2; and

- Fig. 5 is an enlarged fragmentary axial section taken on line 55 of Fig. 2.

Referring especially to Fig. 2, the illustrated burner l comprises an outer tubular body H from which air is discharged to the right as seen I in Fig. 2, a pair of gas and oil tubes l2 and I3 within the body discharging their respective fuels into the air stream, and a spreader baiile l4 positioned in the path of fuel discharge for controlling the mixture of fuel and air and the characteristics of the produced flame. The air passing body H is preferably cylindrical as shown, and of a length sufficient to xtend through the wall of a furnace in which it is to be used. Air enters body near its outer end through an angular air inlet tube l5, and flows axially through the body to discharge from its open inner end I6. Inlet I5 may be connected to any suitable source of relatively low pressure air.

The outer end of body II is partially closed by a transverse end plate ll, which may be attached to the body by a number of circularly spaced screws I8. End plate I! has a central opening I9 within which is threadedly mounted a bushing ring 26 for slidably receiving and guiding the gas delivery tube I2. This gas delivery tube is preferably, like body ll, of straight cylindrical configuration, and has an open discharge end 2| facing in the same direction as the discharge end H; of the body. Near its discharge end, gas tube |2 carries three or more circularly spaced radially projecting positioning members 22 slidably engaging the inner surface of body H to coact with bushing in guiding the gas tube for axial adjusting movement in the body.

The outer end of gas tube l2 beyond bushing 20 is threadedly connected to a T-fitting 23, the upper branch of which is in turn connected to a flanged gas inlet fitting 24. As seen in Fig. 1, this flanged gas inlet fitting is connected to a suitable gas supply line 25 leading from a gas compressor 26.

The outer branch of T-fitting 23 contains a packing assembly. within which oil tube I3 is slidably received, and comprising a body ring 21, a packing ring 28, and a tightening element 29. Near its inner discharge end, oil delivery tube l3 carries three o more positioning projections cooperating with the outer packing assembly to guide the oil tube for axial adjusting movement with gas tube l2. The outer end of oil tube I3 is connected at a location outwardly beyond the packing assembly to a T-fitting 3|, whose upper branch connects with oil supply line 32 leading from oil pump 33. The outer branch of T-fitting 4 3| contains a bushing element 34 through which extends a needle valve control stem 35 having an outer control knob 36.

The needle valve stem 35 extends axially through oil delivery tube l3, and has at its inner end a tapered valve portion I36 seating against a tapered seat 31 within a tubular valve body 38 connected to the inner end of the oil tube. Near its inner tapered end |38, the needle valve threadedly engages the valve body at 39, to permit adjustment of the valv by rotation of its stem. When the valve is in open condition, oil passes about the threaded connection 39 through a number of circularly spaced axially extending recesses 40 in the wall of the valve body.

Th spreader baliie member I4 is carried by and movable with the oil delivery tube l3, by virtue of a threaded connection of member M at its rear end to the needle valve body 38 at i I. Forwardly of this threaded connection, member I4 has a relatively short hollow cylindrical portion 42, at the forward side of which is formed a transverse annular forward wall 43 containing a number of circularly spaced arcuate oil discharge slots 44. The fuel direction portion of member 14 projects forwardly from the transverse annular oil discharge wall 43, and presents a first flaring and preferably frusto-conical outer surface M4, beyond which it presents a preferably cylindrical surface of uniform cross sectional area axially of the body. The reduced end of frusto-conical surface I42 commences at a location radially inwardly of and substantially directly adjacent oil discharge slots 44, so that oil passing from those slots is filmed onto the outer surface of the baffle.

In placing the burner into operation, the oil and gas inlets are connected to an oil pump and gas compressor respectively in the manner illustrated in Fig. l, and a suitable supply of low pressure air is connected to air inlet i5. When needle valve |36 is opened by rotation of control knob 35, fuel oil discharges through slots 44? to be filmed onto and flow along the baffle surface hit. This flaring baiiie surface deflects the oil radially outwardly and into intimate mixture with the air, after which the mixed air and oil are directed in a straight cylindrical discharge path by passage between cylindrical surface 45 of the spreader baffle and the opposed inner cylindrical surface of body Ii. The flame may be changed from this elongated straight cylindrical configuration to a shorter flaring form by axial adjustment of the oil tube and spreader baffle Within body Specifically, the flaring flame is produced when the spreader baiile is moved to a condition in which its cylindrical outer surface 45 is positioned beyond the discharge end of body When a gas name is desired, the oil control needle valve is shut off, and gas is supplied to the device through line This gas flows axially between the gas and oil tubes and is directed against conical baffle surface I44 for deflection outwardly into the air stream. As in the case of an oil flame, the gas flame is caused to be elongated and cylindrical by virtue of its passage between cylindrical baifie surface M and the cylindrical body, and can be adjusted to a short flaring flame by adjustment of the baflie position. Also, the rate of gas flow along the spreader bafiie surface may to a certain extent, be regulated by axial adjustment of gas tube |2 relative to the spreader baflle. If desired, a combination oil and gas flame may be produced by discharging against the baflie member controlled amounts of gas and oil. I claim:

A combination fuel oil and gas burner comprising a tubular body having an open axially inner discharge end and an air inlet near its opposite outer end from which a stream of air flows axially in the body to said discharge end, an annular wall extending transversely across said outer end of the body, a gas delivery tube extending axially in said body and through an opening in said transverse wall to project outwardly therebeyond, means on said gas tube outwardly beyond said wall for connecting the tube to a gas supply line, said tube having an open discharge end in the body facing inwardly in the direction of said open end of the body. means carried by said wall and within the body guiding the tube for axial adjusting movement relative to the body, an oil delivery tube extending axially in and radially spaced from the gas tube and projecting outwardly therebeyond, means on the oil tube outwardly beyond the gas tube for connecting the oil tube to an oil supply line, means mounting said oil tube for axial adjusting movement relative to said body and gas tube, a spreader baflle carried by and projecting downstream from said oil tube and against which oil and gas from said tubes are discharged, said baffle in extending downstream from said tubes having first a substantially frusto-conical radially outer surface flaring downstream from a diameter less than the oil tube to an enlarged diameter greater than the gas tube and then having a substantially cylindrical outer surface of said enlarged diameter, said body having a substantially cylindrical inner surface opposite both of said outer bafile surfaces, a connection between said oil tube and baffle containing a series of circularly spaced passages directing oil from within the tube onto said flaring outer surface of the baffle, and a needle valve in said oil tube for controlling the oil delivery therethrough having a tapered valve portion at substantially the location of said bafile and having an actuating stem extending axially through the oil tube and projecting from the outer end thereof.

GEORGE F. OLSEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,304,402 Spire May 20, 1919 1,329,279 Voorheis Jan. 27, 1920 1,636,597 Fischer et a1. July 19, 1927 1,647,675 Vedder Nov. 1, 1927 1,671,494 Stewart May 29, 1928 

